Development of food packaging bioactive aerogels through the valorization of Gelidium sesquipedale seaweed

This study presents the valorization of the Gelidium sesquipedale seaweed for the development of bioactive aerogels with interest in food packaging applications. The raw seaweed was used to extract cellulose, highly crystalline (Xc similar to 70%) and high aspect ratio (similar to 40) nanocellulose and an agar-based extract, rich in polyphenols and with antioxidant capacity. Subsequently, pure PVA and hybrid aerogels containing cellulose and nanocellulose were produced by a physical cross-linking method. The presence of hydroxyl groups provided by the high aspect ratio of nanocellulose promoted the interactions with water and facilitated the accessibility of moisture towards the interior of the aerogels, hence generating high water sorption capacity materials. The agar-based extract was then incorporated into selected formulations and the release in hydrophobic and hydrophilic food simulant media was investigated. Pure PVA aerogels dissolved in aqueous media, resulting in an immediate release of the bioactive. Interestingly, the hybrid aerogels containing cellulose and nanocellulose preserved their integrity and provided a more gradual release. Although the hybrid aerogels presented similar release profiles during the first 48 h, the presence of nanocellulose led to greater release values after more prolonged times. This shows the promising properties of hybrid PVA/cellulose/nanocellulose aerogels as matrices for the controlled release of bioactive compounds in food systems, which could be of interest for the development of bioactive packaging structures.